Peroxy compounds are effective bleaching agents, and compositions including diperoxyacid compounds are useful for industrial or home laundering operations. For example, U.S. Pat. No. 3,996,152, issued Dec. 7, 1976, inventors Edwards et al., discloses bleaching compositions including peroxygen compounds such as diperazelaic acid and diperisophthalic acid.
Peroxyacids have typically been prepared by the reaction of carboxylic acids with hydrogen peroxide in the presence of sulfuric acid. For example, U.S. Pat. No. 4,337,213, inventors Marynowski et al., issued June 29, 1982, discloses a method for making diperoxyacids in which a high solids throughput may be achieved.
However, granular bleaching products containing peroxyacid compounds tend to lose bleaching activity during storage, due to decomposition of the peroxyacid. The relative instability of peroxyacid presents a problem of storage stability for compositions consisting of or including peroxyacids.
One approach to the problem of reduced bleaching activity of peroxyacid compositions has been to include certain ketones which are said to activate, or catalyze, the bleaching action in peroxyacid bleaching compositions, especially at somewhat lower temperatures than about 90.degree. C. For example, U.S. Pat. No. 4,001,131, inventor Montgomery, issued Jan. 4, 1977, discloses a bleaching composition having a water-soluble organic peroxyacid bleaching agent and a water-soluble diketone activator.
U.S. Pat. No. 4,283,301, inventor Diehl, issued Aug. 11, 1981, discloses bleaching compositions including peroxygen bleaching compounds, such as sodium peroborate monohydrate or sodium perborate tetrahydrate, and activator compounds such as isopropenyl hexanoate and hexanoyl malonic acid diethyl ester. However, these bleach activators tend to yield an unpleasant odor under actual wash conditions, as discussed in U.S. Pat. Nos. 4,486,327, inventors Murphy et al., issued Dec. 4, 1984, 4,536,314, inventors Hardy et al., issued Aug. 20, 1985 and 4,539,130, inventors Thompson et al., issued Sept. 3, 1985. These patents disclose certain alpha substituted derivatives of C.sub.6 -C.sub.18 carboxylic acids which are said to activate peroxygen bleaches and are said to reduce malodor.